Separation Efficiency Of Photocarriers Research Articles

Enhanced photocatalytic performance of SnS2/ZnO Z-scheme composite photocatalysts for efficient environmental remediation

Photocatalysts based on zinc oxide (ZnO) are promising for environmental applications, but their weak photoresponse and low photocarrier separation efficiency limit their practical use. To tackle this issue, we constructed Z-scheme composite photocatalysts of ZnO to boost its photocatalytic performance. We achieved the Z-scheme structure by hydrothermal modification of SnS2 nanoparticles onto ZnO microspheres. Its photocatalytic performance was evaluated through the degradation of Rhodamine B (RhB) under visible light with the assistance of magnetic stirring. The composite photocatalyst exhibited superior performance compared to individual ZnO and SnS2, achieving an optimal degradation rate of 0.0706 min⁻¹. This rate was 15.08 times higher than that of individual ZnO and 10.51 times higher than individual SnS2. Free radical trapping experiments showed that ·O2⁻ and ·OH radicals played a key role in RhB degradation. The Z-scheme composite structure established novel charge transport pathways, guided the migration of photogenerated carriers, and improved spatial separation, thereby enhancing photocatalytic performance. This study provides valuable insights into the design of highly efficient photocatalysts for environmental remediation, offering a promising solution for addressing challenges in pollution control and wastewater treatment.

Enhanced Hg(II) reduction activity over two-dimensional n-n heterojunction MoS2/Bi2WO6 nanocomposites under visible light illumination

The engineering of band structure acts as an effective avenue to promote photocatalytic redox reactions, which can be achieved by fabricating heterojunction photocatalysts. Herein, MoS2 NPs were anchored on the surface of the mesoporous Bi2WO6 network through a facile sol-gel process to form heterostructure MoS2/Bi2WO6 nanocomposites. HR-TEM and XRD results of the obtained MoS2/Bi2WO6 nanocomposite verified the formation of the hexagonal phase of MoS2 and the orthorhombic one for Bi2WO6. The MoS2/Bi2WO6 nanocomposites displayed enhancemed harvest for the visible light domain and photocatalytic ability in comparison with the pristine Bi2WO6. The photocatalytic ability of MoS2/Bi2WO6 nanocomposites was assessed by the Hg(II) reduction upon visible light irradiation. The optimal 12 % MoS2/Bi2WO6 photocatalyst displayed the superior reduction of Hg(II) about 99 % after 50 min, and the rate constant reached 0.1220 min−1 according to pseudo-first-order kinetic, where it was larger three folds than pristine Bi2WO6 (0.0418 min−1). The outstanding photocatalytic ability of n-n heterojunction MoS2/Bi2WO6 photocatalyst was attributed to the huge surface area, wide photoabsorption, and high separation efficiency of photocarriers. The reduction ability of MoS2/Bi2WO6 photocatalyst remained at 94 % after five times recycle, indicating its good reusability and high stability. The obtained heterojunction with the S-scheme mechanism could inhibit the recombination of the photocarriers, thus leading to superb photocatalytic ability. This work emerges an efficient route to design S-scheme heterojunction Bi2WO6-based photocatalytic methods for energy conversion and environmental purification.

Achieving Tunable Band Structure and Photocarrier Dynamics by Regulating 2D Atomic Layer Stacking Toward High‐Performance Self‐Powered Broadband and Deep‐UV Photodetection

Abstract2D materials with unique layer‐dependent electronic structure can bring precise control to their photocarrier dynamics for optimizing and expanding optoelectronic applications, while the challenge of controlling layer stacking makes the layer dependency law still underexplored in emerging 2D ternary metal chalcogenides. Herein, 2D rhombohedral‐phase ZnIn2S4 (R‐ZIS) with controllable layer thickness is achieved by confined‐growth strategy in high yield, exhibiting continuously tunable direct bandgap (2.39–2.77 eV) with evident upshift of conduction band minimum (CBM) and Fermi level (EF), demonstrated arising from the synergistic effect of reduced interlayer interaction with inevitably increasing Zn defects. Remarkably, the carrier dynamics of R‐ZIS in photoelectrochemical (PEC) device is successfully regulated by adjusted CBM and EF, resulting in continuously tunable optical absorption band, photocarrier separation efficiency, self‐powered capability, and dark current noise. Beneficial from tailored band structure and carrier dynamics, self‐powered PEC‐type photodetector with broadband photoresponse (254–765 nm), is achieved fast response speed (12.3/5.3 ms) and high responsivity (90.29 mA W−1) in multilayer R‐ZIS, while deep‐UV photodetector with ultra‐high specific detectivity (1.62 × 1012 Jones) at 254 nm in monolayer R‐ZIS, exhibiting the record performance in both fields. This work motivates the development of tailored band structure for 2D‐materials‐based optoelectronic devices in strategy and mechanism.

Integrating Mo2C/C as cocatalyst into S-scheme Mo2C/C/Co0.5Cd0.5S heterojunction with spatial photocarrier separation for photocatalytic synergistic H2 evolution

Reasonable design and production of potent photocatalysts for sustainable H2 production from solar energy is one of the necessary strategies in the photocatalysis process. The S-scheme heterojunction exposes remarkable superiority in boosting light harvesting and progressing photocarrier separation efficiency in the photocatalyst. Here, new S-scheme heterojunction Mo2C/C/Co0.5Cd0.5S photocatalysts, including different weights of noble metal-free Mo2C/C nanostructures as cocatalysts, were successfully synthesized. As expected, the nanocomposite structures exhibited increased photocatalytic activity relative to single Co0.5Cd0.5S. The nanocomposite containing 5 wt% Mo2C/C exhibited an increased hydrogen production efficiency of 83.86 mmol g−1 h−1, which was 8.4 times higher than single Co0.5Cd0.5S (10.06 mmol g−1 h−1). This implies that for Co0.5Cd0.5S, Mo2C/C increases visible light absorption, facilitates photocarrier separation, and boosts the H2 evolution rate. Moreover, conductive carbon nanoparticles, electron mediators with strong interfacial interaction, serve as rapid photocarrier transfer bridges between Co0.5Cd0.5S and Mo2C. In summary, the superb efficiency of Mo2C/C/Co0.5Cd0.5S is accredited to the synergistic effect between Co0.5Cd0.5S and Mo2C/C, the creation of S-scheme heterojunction, which assists the separation of photocarriers and declines the recombination possibilities. This research ensures a reference and new profound insight for understanding and designing noble metal-free cocatalyst-assisted S-scheme heterojunctions for immensely efficient photocatalytic H2 production.

Metal-Organic Framework with Dual Excitation Pathways as Efficient Bifunctional Catalyst for Photo-assisted Li-O2 Batteries.

Li-O2 batteries (LOBs) have sparked significant interest due to their fascinating high theoretical energy density. However, the large overpotential for the formation and oxidation of Li2O2 during charge and discharge process seriously hinders the further development and application of LOBs. In this work, metal-organic frameworks (MOFs) with different metal clusters (Fe, Ti, Zr) are successfully synthesized, and they are employed as the photoelectrodes for the photo-assisted LOBs. The special dual excitation pathways of Fe-MOF under illumination and the superior separation efficiency of photocarriers, which significantly enhance the activation of O2/Li2O2, improving the catalytic activity of oxygen reduction reaction and oxygen evolution reaction. Moreover, compared to traditional inorganic semiconductor crystals, Fe-MOF exhibits large specific surface area and excellent O2 adsorption ability. Therefore, the LOB with Fe-MOF as the cathode exhibits large specific capacity, ultralow charge/discharge overpotential of 0.22V at 0.05mA cm-2 and excellent stability of 195 cycles under illumination. This study provides an environmentally friendly and highly efficient photocatalyst for LOBs, and a new strategy for designing photoelectrodes.

MXene/ZnS/chitosan-cellulose composite with Schottky heterostructure for efficient removal of anionic dyes by synergistic effect of adsorption and photocatalytic degradation

Nowadays, dye water pollution is becoming increasingly severe. Composite of MXene, ZnS, and chitosan-cellulose material (MX/ZnS/CC) was developed to remove anionic dyes through the synergistic effect of adsorption and photocatalytic degradation. MXene was introduced as the cocatalyst to form Schottky heterostructure with ZnS for improving the separation efficiency of photocarriers and photocatalytic performance. Chitosan-cellulose material mainly served as the dye adsorbent, while also could improve material stability and assist in generation of free radicals for dye degradation. The physics and chemistry properties of MX/ZnS/CC composite were systematically inspected through various characterizations. MX/ZnS/CC composite exhibited good adsorption ability to anionic dyes with adsorption capacity up to 1.29 g/g, and excellent synergistic effects of adsorption and photodegradation with synergistic removal capacity up to 5.63 g/g. MX/ZnS/CC composite performed higher synergistic removal ability and better optical and electrical properties than pure MXene, ZnS, chitosan-cellulose material, and MXene/ZnS. After compounding, the synergistic removal percentage of dyes increased by a maximum of 309 %. MX/ZnS/CC composite mainly adsorbs anionic dyes through electrostatic interactions and catalyzes the generation of •O2−, h+, and •OH to degrade dyes, which has been successfully used to remove anionic dyes from environmental water, achieving a 100 % removal of 50 mg/L dye.

Insight into the synergistic effect of defect and strong interface coupling on ZnIn2S4/CoIn2S4 heterostructure for boosting photocatalytic H2 evolution

Steering the directional carrier migration across the interface is a central mission for efficient photocatalytic reactions. In this work, an atomic-shared heterointerface is constructed between the defect-rich ZnIn2S4 (HVs-ZIS) and CoIn2S4 (CIS) via a defect-guided heteroepitaxial growth strategy. The strong interface coupling induces adequate carriers exchanging passageway between HVs-ZIS and CIS, enhancing the internal electric field (IEF) in the ZnIn2S4/CoIn2S4 (HVs-ZIS/CIS) heterostructure. The defect structure in HVs-ZIS induces an additional defect level, improving the separation efficiency of photocarriers. Moreover, promoted by the IEF and intimate heterointerface, photogenerated electrons trapped by the defect level can migrate to the valence band of CIS, contributing to massive photogenerated electrons with intense reducibility in HVs-ZIS/CIS. Consequently, the HVs-ZIS/CIS heterostructure performs a boosted H2 evolution activity of 33.65 mmol g−1 h−1. This work highlights the synergistic effects of defect and strong interface coupling in regulating carrier transfer and paves a brave avenue for constructing efficient heterostructure photocatalysts.

Bifunctional phosphate-modulated Cu2O/CeO2 redox heterojunction: A promising approach for proficient CO2 reduction

The construction of extremely dispersed redox-heterojunctions is a critical step toward improving of photocatalytic activity. Nonetheless, electron transfer faces momentous hurdles at the interfaces of these redox-heterojunction, mainly as a result of the considerable gap and potential-barrier between them. To address this obstacle, a bifunctional phosphate was deliberately introduced as an electron-bridge into the Cu2O/CeO2 redox-heterojunction system, aiming to necessitate a potential-barrier, establish a photoelectron transport route to improve the surface catalysis, and serve as a catalyst stabilizer, leading to improved dispersion of Cu2O on the CeO2 surface. The resultant intricately dispersed and optimized redox-heterojunction showcased an unparalleled advancement in apparent quantum efficiency (AQE), attaining an approximate value of 1.41 % at 420 nm during the photocatalytic CO2 reduction. The experimental findings established a conspicuous association between the substantial increase in AQE and the diminished interfacial migration resistance, heightened dispersion, and abundance of more active-sites, all accredited to phosphate-modulation in the redox-heterojunction. The work emphasizes the significant importance of phosphate in bridging the conduction and valence bands of semiconductors, leading to enhanced photocarrier separation efficiency and improved molecular dispersion.

Novel mesoporous Pt@n-AgI/n-α-MoO3 ternary nanocomposite for enhanced hydrogen production from glycerol under visible illumination

A novel mesoporous n-AgI/n-α-MoO3 nanocomposites with large surface area were constructed by hydrothermal approach utilizing hexamethylenetetramine (HMT) as an organic building block (cage-like). Pt nanoparticles (NPs) were highly distributed over AgI/α-MoO3 nanocomposites in situ during the photocatalysis reaction for photocatalytic H2 evolution under visible exposure. The H2 evolution results indicated that 9%AgI/α-MoO3 nanocomposite exhibited the best H2 evolution ability, and the total H2 amount was determined at about 24100 μmolg−1 within 9 h illumination using 1 g/L the photocatalyst dosage, which increased to 28920 μmolg−1 at 2.5 g/L. The H2 amount of AgI/α-MoO3 photocatalyst was fostered ∼40 and 10 times larger than that of α-MoO3 and AgI NPs. The optimal 9%AgI/α-MoO3 (2521.8 μmolg−1h−1) presented 34.4 and 8.61 times higher H2 evolution rate compared to α-MoO3 (73.23 μmolg−1h−1) AgI (292.91μmolg−1h−1). The resultant S-scheme AgI/α-MoO3 heterojunctions enhanced the separation efficiency of photocarriers with a remarkable enhancement of H2 evolution. The n-n heterojunction AgI/α-MoO3 nanocomposite inhibited the recombination of electrons and holes, decreased photoluminescence intensity, enhanced the current density, and promoted photocatalytic ability. The obtained AgI/α-MoO3 nanocomposite can maintain stability for 45 h of illumination continuously in the photocatalysis reactions for five consecutive cycles. These results provide a simple approach to designing S-scheme photocatalysts with a high separation rate of carriers to promote solar energy conversion efficiency.

Ultrasensitive Photocathodic Biosensor Based on the Cu2O/PTB7-Th/PDA+ Composite with Enhanced Photoelectrochemical Performance for the Detection of MicroRNA-375-3p.

Herein, an ultrasensitive photocathodic biosensor was fabricated based on Cu2O/PTB7-Th/PDA+ photoactive materials with high photocarrier separation efficiency for the detection of microRNA-375-3p. Impressively, the photocathodic signal of the Cu2O material was significantly enhanced by using PTB7-Th as an energy level-matching photoactive material to enhance the bulk charge separation and N,N-bis (2-(trimethylammoniumiodide) propylene) perylene-3,4,9,10-tetracarboxydiimide (PDA+) as an interfacial charge transfer mediator to efficiently suppress charge recombination at the photoelectrode/electrolyte interface. Compared with the pristine Cu2O as a photocathode, the obtained Cu2O/PTB7-Th/PDA+ exhibited a 17 times higher photocathodic signal. As a proof of concept, a PEC biosensor was fabricated by using Cu2O/PTB7-Th/PDA+ as a photoactive material and a target-triggered 3D DNA walker integrated with the dumbbell hybridization chain reaction (DHCR) as a signal amplifier to achieve the sensitive detection of microRNA-375-3p with a detection limit of 0.3 fM. This work provided a method to increase the photocurrent signal and the sensitivity of PEC-sensing platforms for the detection of biomarkers and disease diagnosis.

In situ fabrication of S-type BiOI x Br y heterojunction with metallic Bi for boosting photocatalytic activity for CO2 reduction

Heterojunction construction and morphology control have always been considered effective ways to promote the capability of photocatalysts. In this work, BiOI x Br y , S-type heterojunction photocatalysts with metallic Bi nanoparticles, were synthesized in situ using a solvothermal method, and the influence of reaction temperature (180 °C–220 °C) and dopant doping amount on the catalysts’ microscopic morphology, structure, and catalytic properties were researched. Study results revealed the 1:1 BiOI x Br y synthesized at 200 °C exhibited the optimum behavior in CO2 reduction. Its catalytic CO2 reduction to CH3OH was 932.88 μmol gcat −1 and C2H5OH was 324.46 μmol gcat −1 under the analog light source for 8 h, which was approximately 1.92 and 1.49 times higher than that of BiOI-200 °C, respectively. The reinforced catalytic properties are probably attributed to the synergistic effect between metallic Bi nanoparticles and BiOI x Br y heterojunction. Thanks to the SPR effect of in situ metallic Bi, the catalysts’ photocarrier separation efficiency is facilitated. Additionally, the heterojunction formation contributes to that trend and more importantly, preserves the charge carriers with strong redox capacity in BiOI x Br y , proving product selectivity. We also present a potential electron transfer mechanism involved in the BiOI x Br y photocatalytic CO2 reduction based on the characterization analysis and experimental results.

Precise Defect Engineering on Graphitic Carbon Nitrides for Boosted Solar H2 Production.

Defect engineering has been regarded as an "all-in-one strategy" to alleviate the insufficient solar utilization in g-C3N4. However, without appropriate modification, the defect benefits will be partly offset due to the formation of deep localized defect states and deteriorated surface states, lowering the photocarrier separation efficiency. To this end, the defective g-C3N4 is designed with both S dopants and N vacancies via a dual-solvent-assisted synthetic approach. The precise defect control isrealized by the addition of ethylene glycol (EG) into precursor formation and molten sulfur into the pyrolysis process, which simultaneously induced g-C3N4. with shallow defect states. These shallow defect energy levels canact as a temporary electron reservoir, which are critical to evoke the migrated electrons from CB with a moderate trapping ability, thus suppressing the bulky photocarrier recombination. Additionally, the optimized surface states of DCN-ES arealso demonstrated by the highest electron-trapping resistance (Rtrapping) of 9.56×103 Ω cm2 and the slowest decay kinetics of surface carriers (0.057s-1), which guaranteed the smooth surface charge transfer rather than being the recombination sites. As a result, DCN-ES exhibited a superior H2 evolution rate of 4219.9µmol g-1 h-1, which is 29.1-fold higher than unmodified g-C3N4.

Improved photocarrier separation in Ga/Fe gradient (Ga, Fe)2O3 thin films

Metal oxides are promising photoanode materials for photoelectrochemical reactions due to their chemical stability and low-cost synthesis. However, their high photocarrier recombination rate limits their commercial applications. One strategy to promote photocarrier separation efficiency in metal oxides is building an inner electric field through band engineering techniques. In this study, a gradient band structure was prepared in (Ga, Fe)2O3 thin films on F:SnO2 (FTO) coated glass substrate by varying the Ga/Fe ratio. The performance of the gradient photoanode was evaluated by measuring its photocatalytic activity with photocurrent. The forward gradient photoanode, with increasing Ga/Fe ratio from bottom substrate to photoanode surface, exhibited a higher photocurrent density (0.44 mA/cm2 at 1.23 V vs reversible hydrogen electrode (RHE) under AM 1.5G illumination) compared to the reverse gradient photoanode with decreasing the Ga/Fe ratio in the same situation. The forward gradient band structure, which facilitates photocarrier separation and transportation, was believed to play a dominant role in improving the photocatalytic performance. This work demonstrates an effective strategy to improve photocarrier separation and photocatalytic performance of metal oxide photocatalysts through band engineering.

Design of lateral and vertical Bi4O5I2/BiOCl heterojunctions with different charge migration pathway for efficient photoredox activity

As 2D heterojunction photocatalysts, lateral heterojunctions (LHs) formed based on chemical bonding generally exhibit much higher photocarrier separation efficiency than vertical heterojunctions (VHs) formed by van der Waals bonds. However, little is known about the different detailed interfacial structures and photocarrier separation mechanisms of the two heterojunctions. Herein, 2D BiOCl and Bi4O5I2 were selected as model building blocks to construct BiOCl/Bi4O5I2 VHs and LHs. The LHs with direct charge carrier transport channels show stronger interfacial electric field and higher charge transfer efficiency than the VHs. The photogenerated charge carrier migration pathway in the LHs follows a Z-scheme model, while the VHs fits a type II model. As a result, the BiOCl/Bi4O5I2 LHs exhibited higher redox performance than the VHs, which is 1.55, 1.56 and 2.1 times better for H2 production, Cr(VI) photoreduction and phenol photodegradation, respectively. This study demonstrates a new approach to constructing highly efficient facet-dependent 2D heterojunction photocatalysts.

Effect of Co3O4/TiO2 heterojunction photoanode with enhanced photocathodic protection on 304 stainless steel under visible light

The Co3O4/TiO2 compound photoanodes were prepared by anodization and low-temperature hydrothermal method for the photocathodic protection of 304 stainless steel (304SS). The effect of Co3O4 loading on corrosion resistance of 304SS in 3.5 wt% NaCl was studied by changing the cobalt nitrate concentration of hydrothermal solutions, where the photoanodes were immersed in 0.1 M Na2S+ 0.2 M NaOH solution during tests. Compared with pure TiO2, Co3O4/TiO2 shows stronger visible-light absorption, higher separation efficiency of photocarriers, and better corrosion protection in dark. When cobalt nitrate concentration is 1 mM in the reaction solution, the compound exhibits the best protection performance with a coupled potential under illumination/dark of –0.69/–0.45 VSCE. This enhanced corrosion resistance is not only due to the staggered p-n heterojunction at Co3O4/TiO2 interface but also due to the excellent optical absorption activity and electronic storage capacity of Co3O4. Specifically, the p-n internal electric field drives the photoelectrons to flow to the 304SS under illumination. Meanwhile, it triggers the reverse flow once the light is removed. The latter electrons are stored by Co3O4 and then slowly released in the dark, thus realizing the delayed protection. This work provides theoretical support and possible guidance for the design and application of p-n junction photoanode in the photocathodic protection field.

Spontaneous polarization of ferroelectric heterostructured nanorod arrays for high-performance photoelectrochemical cathodic protection

Corrosion is a critical global problem for the steel industry and a grand challenge toward Net-Zero clean growth. TiO2 nanorods (TNRs) have been developed for photoelectrochemical cathodic protection (PCP) of coupled metal. However, the performance was hindered by their wide bandgap, weak visible-light response, and low separation efficiency of photocarriers. In this work, a unique multilayered coaxial nanorod array (TNRs/BTO/Ag NPs) structure has been proposed to enhance ‘hot’ electrons injection via inserting a ferroelectric semiconductor BaTiO3 (BTO) nanolayer between TNRs and Ag nanoparticles (Ag NPs). The spontaneous ferroelectric BTO nanolayer built a polar charge-induced electric field (PEF), resulting in a strong spontaneous polarization. Furthermore, the as-proposed structure can negatively shift the surface potential of the coupling 304 stainless steel by 0.80 V relative to its corrosion potential under simulated solar light illumination which is the record PCP potential among reported works. Based on comprehensive electrochemical and theoretical studies, the origin of the enhanced photo-generated carriers’ separation and depletion to the coupled metals is attributed to a synergic effect between PEF (the spontaneous polarization of BTO) and internal electric field (IEF) resulting from the cascade energy band alignment. Various promising applications can be envisioned from as-proposed multilayered coaxial nanorod array photoelectrodes.

Phenyl-doped porous carbon nitride for enhanced visible light-driven photocatalytic oxidation of aromatic alcohols

The g-C3N4 is one of the most promising photocatalytic materials in the recent decades，but its development is limited by its low carrier separation efficiency. The doping of g-C3N4 is a very effective way to regulate its photoelectric properties. Here, the phenyl was successfully doped into basic structural unit heptaazine ring of g-C3N4 by co-polymerization strategy. It was found that the presence of benzene ring increased the BET surface area (75.8 ​m2 ​g−1) of porous C3N4, enhanced the visible light absorption, narrowed the band gap and improved the photocarrier separation efficiency. The improvement of these properties enhances the photoelectric properties of pure g-C3N4.The phenyl-doped porous C3N4 exhibits excellent photocatalytic activity for selective oxidation of benzyl alcohol. When the addition mass of 2-aminbenzonitrile is 0.3 ​g, the conversion rate of benzyl alcohol reaches 94.5% under 8 ​h of solar radiation, which is about 2.1 times that of pure porous C3N4.

Activation of oxalic acid via dual-pathway over single-atom Fe catalysts: Mechanism and membrane application

Oxalic acid (OA), together with its ligand, appears in diverse biotic and abiotic processes in nature. However, the applications of the photochemical property of OA and its complexes in environmental purification are scarce. Herein, we reported a Fe single-atom catalyst with Fe-N4 configuration supported on g-C3N4 (Fe-CN) to activate OA for ultrahigh-efficiency removal of Cr(VI) under visible light irradiation through dual pathways: the photo-dissociation of [FeⅢ(C2O4)]+ and the reaction between OA and photogenerated holes, achieving the generation of •CO2-. The introduction of Fe-N4 favors the formation of configuration [FeⅢ(C2O4)]+ and fabricates the electron transfer channel from catalyst to OA, further decreases the energy barriers of •CO2- generation, and thereafter efficiently facilitates the C-C cleavage for the generate of •CO2-. Meanwhile, the strong coordination interaction over Fe single atoms and N atoms could enhance the separation efficiency of photo-carriers and further promote the reduction activity. Under optimal conditions, Fe-CN showed a 5.1-fold increasement in photocatalytic kinetics contrast to pristine CN. The Fe-CN catalyst attached on fibrous membrane for treatment of flowing Cr(VI) wastewater exhibits 90% reduction efficiency over 10 h, which is expected to facilitate the practical application of the catalyst. The mechanism of OA activation with dual-pathway was unveiled by in-situ Fourier transform infrared spectra and theoretical calculations. This work provides an important guidance for the application of OA and its complexes to achieve the attenuation of toxic and harmful heavy metal in water restoration.

CoV‐LDH‐Derived CoP2 Active Sites and ZnxCd1−xS Solid‐Solution Ingeniously Constructed S‐Scheme Heterojunction for Photocatalytic Hydrogen Evolution

AbstractEstablishing efficient charge‐transfer channels that provide sufficient active sites to enhance the activity of photocatalysts remains a challenging problem. In this work, n‐type CoP2 semiconductors as one of the main active components for efficient hydrogen evolution are obtained from bulk P‐CoV‐LDH. The emergence of CoP2 semiconductors not only enriches the active sites but also carries a large amount of negatively charged P, which can act as a base to seize more protons, thereby accelerating the precipitation of hydrogen. To achieve oriented control of carrier migration, the ZnxCd1−xS solid solution is effectively combined with P‐CoV‐LDH for the first time to synthesize a highly efficient and stable S‐scheme heterojunction photocatalyst. The best P‐CoV‐LDH/ZnxCd1−xS 30% composite has a hydrogen evolution rate of 1244.3 µmol without noble metal additives, which is 6.4 times more than ZnxCd1−xS. S‐scheme heterojunctions exhibit remarkable photocarrier separation efficiency and low interfacial migration resistance.

A novel strategy of hydrothermal in-situ grown bismuth based film on epoxy resin as recyclable photocatalyst for photodegrading antibiotics and sterilizing microorganism

Various photocatalyst powders (such as bismuth oxide/bismuth oxyiodide) can remove contaminants and microorganism from waterbody efficiently, but their practical application was limited due to poor recovery performance. To address this problem, we reported the construction of epoxy resin induced hydrothermal in-situ growth Z-scheme bismuth oxide/bismuth oxyiodide heterostructure film on various metals as a recycled photocatalysts. Novel epoxy resin was proposed to substitute in-situ growth film of seed layer constructed by magnetron sputtering and electrodeposition between film and metals. The universal flower-like microspheres (diameter: 3–5 μm) bismuth oxide/bismuth oxyiodide films (thickness: 13 μm) were grown on various metals. Additional film decorated by photothermal catalyst nanoparticles (such as Ag, diameter: 200 nm) was constructed. The metal/epoxy resin/film can efficiently photodegrade 83.8% of Rhodamine B (RhB) and 73.2% of triclosan (TCS) within 210 min under the visible light illumination. Furthermore, antimicrobial efficiency of bismuth oxide/bismuth oxyiodide neglected in the reported study was assessed and exhibited inactivation of >99.99% Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at 6 h and 9 h of irradiation. The Z-scheme heterostructure film can simultaneously produce O2− and OH. In addition, there was a synergistic effect between the film and the silver nanoparticles, silver nanoparticles can not only further enhance the separation efficiency of photocarriers and generation efficiency of free radical, but also form silver ions to further improve the antimicrobial property. Therefore, metal/epoxy resin/film had broad application prospects as an easily recycled photocatalyst and can also be adopted to prepare other films for photocatalytic application.